Many techniques are available for sediment examinations, however few techniques combine non-destructive features, a wealth of important information available down to the microscopic scale, and time for examination that is short enough to offer large sample throughput, and not to damage the valuable sediment cores during examination. A combination of these features has made XRF core scanning the standard tool for examination of sediment cores, often used as a first sample overview from which scientists can decide for the following steps to take when examining their samples.
The nature of ocean sediments emphasizes the need of high resolution XRF scanning, since every downcore millimeter of deep sea sediment contains information from very many years.
With onboard core scanner installations, core examinations can even be performed while the core sampling vessel is still at the sampling spot, and an overview scan with centimeter steps can be performed within a few minutes, depending on the choice of XRF scanner. Data on the variation of different elements along the cores, when combined in a way to describe proxies, provide much information of the origin of the different sediment sections. The list of aspects on climate related information that can be retrieved through proxies has grown much in the last few years, and 60+ proxies have been listed.
Here are shown a few data examples from Itrax Core Scanner. These data are from analysis of a section of a marine sediment core from the Arctic,and give an idea of the level of accuracy and detail of core data that can be gathered in short time . The photos were recorded with Itrax Core Scanner. The two photos show the same 200 millimeter long sediment section. In the left one of these, two element profiles in Red and Blue are overlaid on the photo, showing the variation of Silica (Si) concentration along the sample as determined in two consecutive scans. The Si concentration is on average roughly 10%. The right photo shows the same sample section, here with two Manganese (Mn) profiles overlaid. The two Mn profiles were registered during the same two scans as for Si. Together they give an idea of the level of reproducibility for light as well as heavier elements, when scanning with one second of measuring time per point. The Mn concentration is on average roughly 0.07% (700 PPM).
The elements that were determined simultaneously in one scan were Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Br, Rb, Sr, Zr, Ba, La and Pb (only Si and Mn shown). Imprints from the Magnetic Susceptibility measurement appear as circular marks on the sample surface, while Itrax optical, radiographic and XRF analyses do not touch the surface during analysis.These measurement were conducted with an Itrax Core scanner equipped with our top-of the-line XRF offering a count rate of up to 350.000 x-ray photon counts per second, thereby offering very fast and at the same time precise analyses. Please click this link to open a larger sample image in a separate window Core material with courtesy of Dr. Richard Gyllencreutz, Stockholm University. From IODP Expedition LOMROG III 2012, Lomonosov ridge, off Greenland. Sampled at 4228 meters depth.